The figure I heard was 55, which means some states have more than one Springfield, or they're counting Norths, Souths, Easts, Wests, News, etc.

However, only some Springfields were qualified to be in the contest because the chosen one had to have a cinema. There are a lot of rinky-dinky Springfields out there, such as Springfield, New Hampshire, population 1100. Other Springfields did not petition or declined the invitation. For instance, Springfield, Minnesota, issued a statement saying it was above all that; they're too good to be the Simpsons' hometown! What? That's like saying you're too good to be America's hometown! Boycott Springfield, Minnesota! :D